I’ve been tolerant of a very minor auto trans leak for a long time. It was from the fill tube nut and flange. I had to used the original 56 even on the 62 C-O-M I had installed and the very minor leak was still there. I needed to put the car up in the air to change a failed oil light sender and check the oil pressure relief so while it was up I decided to install the new tube and dipstick I bought from Larry’s T-Bird parts while ago. I might have been taking a chance because no mention was made to any year passenger car. The tube fit fine and the leak is gone.
I could never see anything wrong with the old mating surfaces but something was there and no matter how tight I tried it leaked. Glad that’s done.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

The Flare  end of your Tube must have been worse than Mine. I thought about using an O- ring or Copper Washer also but luckily Tape and Sealant worked. I knew that new Dipsticks were available. Didn't know the Tube was also. Good to know.